This proposal is to provide continuation support for research into applications of mass spectrometry in Endocrinology and Metabolism. This research will include five objectives: (1) basic developmental research into mass spectrometry of hormonal peptides, proteins and steroids; (2) collaborative studies on investigation of steroid biosynthesis and metabolism in patients with endocrinopathies; (3) studies of in vitro metabolism of steroids in cellular or enzyme preparations; (4) characterization of proteins and glycoproteins of importance in steroid and metabolic research and (5) metabolic studies using stable isotopes. We are in a unique position to forward the first objective (development research). During the tenure of the current grant we were successful on two occasions (1987, 1991) in obtaining new mass spectrometers through the Shared Instrumentation Grant program (thermospray/FAB quadrupole mass spectrometer, electrospray HPLC/MS). These instruments in addition to our GC/MS allow us to analyze a full complement of analytes from unconjugated steroids through polar steroid conjugates and hormonal peptides to intact proteins. The increased capabilities of our facility will permit us to enter new fields. In one instance we want to develop new mass spectrometric methods based on the new electrospray MS technique. This will include combining micro- or capillary HPLC with the new instrumentation. Using this technology it may be possible to achieve the sensitivity required to determined intact steroid conjugates of clinical importance (e.g. androstanediol glucuronide). The availability of electrospray MS will allow us to enter the protein identification area since analysis of both intact proteins, tryptic peptides and determination of glycoprotein structures will be possible. Combination with micro- or capillary HPLC will allow this to be conducted on picomole amounts of components.